Hi…I’m not an expert in Chicken medicine, but I’ve been an ER nurse for longer than I care to mention

. The only thing that I can think of that sounds similar in a human condition…would be a secondary irritation/superinfection due to antibiotics…sort of like when women get yeast infections after taking meds for a UTI, or when people develop a type of colitis called clostridium difficile after taking a long course of antibiotics for a Pneumonia or a blood infection. Have you tried adding a probiotic like the ones made by sav-a-chic or purina to her water? Just throwing darts…i hope your sweet hen recovers quickly